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Statistics just released (see below) reveal that Oregon experienced a total of 18 algal bloom advisories during 2011, resulting in use of the affected lakes being constrained for a total of 1179 days, an average of 65 days per lake! This must have had massive economic implications as two months of lost business during the summer season is a lot. Three of the lakes were under advisory for more than 160 days. The total was, however, 237 days less than that for 2010 – but with the data showing a massive increase since 2005. Total days under advisory doubled between 2007 and 2008, and again from 2009 to 2010.

The bulk of the warnings occurred in western Oregon which, I assume, is the more populated part – i.e. more pollution, but I stand to be corrected here.

Oregon is one of the states that has changed the rules for the issuing of algal warnings, now requiring that algal toxins be present before the advisory is issued. I am not at all sure that this is a wise decision but I do understand the desperation at wanting to keep lakes useable for as long as possible. My concerns relate to, inter alia, the absence of real-time ability to check for toxins- getting the results takes a few days in most cases although it is possible to “dip-stick” test for most toxins, at the lakeside, within half-an-hour. Secondly, blue-green algae produce a whole lot of nasty compounds, not just the common toxins we tend to focus on. So, the new rules do not provide a 100% reliable test for allowing human contact with the water. I have been involved with cyanobacterial toxins for 30 years and have seen some nasty effects where no toxins were detected – most commonly dermatitis and skin blistering.

I would urge lake managers in Oregon and elsewhere to use multiple criteria to evaluate the conditions and, at the very least, use rapid test kits onsite, backed up by laboratory analyses. Big lakes with big economies should consider setting up their own dedicated laboratories.